A Nano Fish Story?

Nanotechnology groups and websites are talking about a "catch and release" method developed by NIST researchers to capture metal-based nanoparticles on a surface in a layer only one particle thick, then release them at the desired moment. This would allow scientists to expose cell cultures to them to test for health hazards.

NIST, a Commerce Department agency, posted an article about this June 7. The contact for more information about it is Chad Boutin, 301-975-4261.

The article says the National Institute of Standards and Technology (NIST) team used a mild electrical current to capture gold nanoparticles on a gold surface covered by long, positively charged molecules. The nanoparticles were coated with citrate molecules with a slight negative charge that draws them to the surface covering, but the attraction can be broken with a slight electric current. "The method also has the advantage of collecting the particles in a layer only one particle thick, which allows them to be evenly dispersed into a fluid sample, thereby reducing clumping —- a common problem that can mask the properties they exhibit when they encounter living tissue," it says, quoting NIST physicist Darwin Reyes as saying the method should be particularly useful in toxicology studies.

"Many other methods of trapping require that you modify the surface of the nanoparticles in some way so that you can control them more easily," Reyes says. "We take nanoparticles as they are, so that you can explore what you've actually got. Using this method, you can release them into a cell culture and watch how the cells react, which can give you a better idea of how cells in the body will respond."

Other methods for studying nanoparticles' toxicity do not enable such precise delivery of the particles to the cells, it says. The surface covering can be designed to attract different materials and thus be used with a variety of nanoparticles.